1. Field of the Invention
The present invention relates to a refrigerating system, and more particularly, to a refrigerating system for retrieving energy lost when pressure necessary to make refrigerant flowing is changed from high pressure to low pressure to enhance energy efficiency, and reusing the energy as a power source for increasing the pressure again.
2. Background of the Related Art
In general, a compressor in a refrigerating system compresses and pumps refrigerant. The refrigerant compressed by the compressor becomes gaseous refrigerant while passing through a capillary tube or an expansion valve, for example. The conventional refrigerating system employing such a refrigeration cycle causes many problems in circulating the refrigerant. That is to say, whereas external power is required when the pressure necessary to make the refrigerant of the refrigerating system flowing is changed from low pressure to high pressure, the pressure is naturally decreased when the pressure necessary to make the refrigerant flowing is changed from high pressure to low pressure such that power loss occurs unnecessarily. In further detail, the power used in the conventional refrigerating system serves to only increase the pressure of the refrigerant. However, since the pressure necessary to make the refrigerant flowing is hydro-dynamically changed from high pressure to low pressure through the capillary tube or the expansion valve as a natural result, the power used to increase the pressure of the refrigerant is lost as a whole.
In other words, energy necessary when the pressure of the refrigerant is changed from high pressure to low pressure is the same as that necessary when the pressure of the refrigerant is changed from low pressure to high pressure. Thus, if the energy lost when the pressure of the refrigerant is changed from high pressure to low pressure is retrieved and reused, the energy efficiency of the refrigerating system will be accordingly enhanced. Also, if the retrieved energy is used for the compressor, energy to be used for the compressor is proportionally saved, thereby improving the energy efficiency of the system.
However, the refrigerating system is not actuated based on such a simple principle or devices as we can imagine, and not be actuated by using simple pressure, such as high pressure and low pressure. The refrigerating system is called a heat pump for transferring heat by circulating refrigerant inside the refrigerating system to change the pressure and state of the refrigerant.
When the refrigerant circulates through long coils and various types of devices in the system, there is generated resistance against passage of fluid, i.e., pipe resistance. In an energy-exchanging device for changing between low pressure and high pressure, there are generated friction loss in a rotation unit, heat loss and a decrease in capacity efficiency. When the refrigerating system is provided with an auxiliary compressor for compensating for the loss and an auxiliary motor mounted on a rotary shaft of the energy-exchanging device when pressure is changed from low pressure to high pressure for compensating for the loss, the necessity of a motor having high power is eliminated.
If such a refrigerating system is realized based on the above theory, a conventional absorption cooling system or a chiller-heater of an absorption refrigerating system using water, ammonia or lithium bromide will not be required any more. The problem of a decrease in engine load and speed of a car and a continued ratio caused when an air conditioner is used in the car in summer will be solved as well. The shortage of power supplied and demanded in summer due to an increase in the use of refrigerating systems will be also solved.
A conventional refrigerating system will be described as follows with reference to FIG. 14.
Referring to FIG. 14, the conventional refrigerating system includes a compressor 10 for compressing gaseous refrigerant under high temperature and high pressure up to condensing pressure, a condenser 12 for condensing the gaseous refrigerant compressed by the compressor 10 into a liquid state through an air blast of a cooling fan 12a to release heat (if the condenser is a water-cooled type, it uses water instead of air to condense the refrigerant. Even though other cooling agents or devices can be used, the present embodiment uses air for explanation.), an expansion valve 24 for expanding the liquid refrigerant condensed by the condenser 12 under high temperature and high pressure into gaseous refrigerant under low pressure by throttling action, and an evaporator 26 for evaporating the gaseous refrigerant expanded by the expansion valve 24 while cooling air which is blasted by a blast fan 26a using evaporating heat of the refrigerant by heat exchange, and returning the gaseous refrigerant to the compressor 10.
In the meantime, the refrigerant should be continuously changed between a gaseous state and a liquid state during the refrigeration cycle. When the refrigerant contains water, the water is frozen in the expansion valve or the capillary tube while circulating through the refrigerating system during the refrigeration process, thereby causing a shut-off of the refrigeration cycle and stopping the refrigerating system. Since the state of the refrigerant cannot be changed smoothly, the refrigerating system cannot be operated well and may be rusted. In case of the refrigerating system employing ammonia, if water is permeated thereinto, dilution occurs due to ammonia water. Therefore, if the amount frozen is small, it will not stop the refrigerating system. However, since evaporating pressure is increased during the dilution, water separation needs to be done.
To solve the problem due to the water, the conventional refrigerating system is provided with a drier (for adsorbing porous material, such as silica gel) interposed between the condenser 12 and the expansion valve 24 in order to adsorb the water contained in the refrigerant, and a fluid receiving tank 15 interposed between the condenser 12 and the drier 18 for supplying only the liquid refrigerant to the expansion valve 24.
The drier 18 has a desiccant and a filter embedded therein, and the desiccant absorbs the water from the refrigerant introduced from the condenser 12 toward the expansion valve 24 and the filter filters impurities, except water, contained in the refrigerant.
The fluid receiving tank 15 temporarily stores the liquid refrigerant dealing with a load variation of the refrigeration cycle, separates pre-condensed refrigerant or non-condensable gas contained in the liquid refrigerant, and protects the system by forcibly discharging the refrigerant by means of a fusible plug, if any, when the refrigerant is overheated due to failure of the system.
Meantime, when the gaseous refrigerant discharged from the evaporator 26 is not completely evaporated, water is contained in the discharged gaseous refrigerant. Therefore, since the gaseous refrigerant existing in a pipe line between the evaporator 26 and the condenser 10 is changed into a liquid state when the refrigerating system is stopped, the water may be introduced into the compressor 10.
However, since the water is incompressible fluid, when the water is introduced into the compressor 10, there is generated a liquid compression phenomenon in which a so-called hammering noise is made, and there is caused the burning in the compressor 10 because the water is not compressed.
Accordingly, it is necessary to fundamentally prevent the liquid refrigerant from being introduced into the compressor 10. To do that, a gas and liquid phase separator 29 is interposed between the evaporator 26 and the compressor 10 for separating the liquid refrigerant and supplying only the gaseous refrigerant to the compressor 10.
To protect the compressor 10 from being damaged when impurities are introduced into the compressor 10, a filter 32 is interposed between the gas and liquid phase separator 26 and the compressor 10 for filtering the impurities.
Reference numeral 16 designates a solenoid valve for preventing the refrigerant from being discharged through the fluid receiving tank 15, and reference numeral 22 designates a sight glass.
In the conventional refrigerating system, there is caused huge resistance when the refrigerant passes through the fluid receiving tank 15, the drier 18 and the solenoid valve 16. And, there is caused a severe change in pressure due to the alternating flow of filled state and semi-filled state when the refrigerant arrives at the right front of the expansion valve 24 due to its control of the amount of refrigerant even though the refrigerant is filled with only water when passing through the fluid receiving tank 15.
To ensure prevention of the resistance and pressure change, the fluid receiving tank 15 is excessively filled with the water. In this case, disadvantageously, the volume of the fluid receiving tank 15 is increased and the amount of refrigerant charged is also increased. Since the amount of Freon used is restricted since Montreal Protocol (which limits the use of Freon refrigerant which depletes the ozone layer), it is necessary to develop a refrigerating system using a small amount of Freon charged.
Further, in the conventional refrigerating system, the gas and liquid phase separator 29 interposed between the evaporator 26 and the compressor 10 is structured in such a manner that a gas and liquid phase separating pipe installed therein is bent in the shape of U so as to prevent the liquid refrigerant from being introduced thereinto.
Accordingly, the present invention is directed to a refrigerating system that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a refrigerating system for retrieving energy lost when pressure necessary to make refrigerant flowing is changed from high pressure to low pressure in order to enhance energy efficiency and reusing the energy as a power source for increasing the pressure again.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a refrigerating system comprising: a refrigerant circulating part having a compressor for compressing refrigerant, a condenser for condensing the refrigerant and an evaporator for evaporating the refrigerant; a plurality of magnet valves connected to the output part of the compressor and the output part of the condenser for measuring the temperature and pressure of a part of the refrigerant discharged from the compressor and condenser; a plurality of by-pass pipes communicating with the magnet valves and operated under the control of the magnet valves for by-passing the part of the refrigerant to the compressor in order to recompress it; and an ejector connected to the by-pass pipes and the evaporator for ejecting the part of the refrigerant fed from the by-pass pipes and the refrigerant fed from the evaporator back to the compressor based on the venturi principle to compensate for reduced energy of the compressor.
It is desirable that the refrigerating system further includes a controller for controlling the overall operation of the refrigerating system.
It is desirable that the refrigerating system further includes a housing interposed between the ejector and the compressor and connected to the output part of the condenser and the input part of the evaporator for completely evaporating the refrigerant flowing from the evaporator and passing therethrough.
It is desirable that the refrigerating system further includes a first pump interposed between the ejector and the compressor for increasing the pressure of the refrigerant flowing from the ejector and a second pump interposed between the condenser and the evaporator and coaxially disposed with the first pump for expanding the refrigerant flowing from the condenser.
It is desirable that the refrigerating system further includes a motor interposed between the first pump and the second pump.
It is desirable that the refrigerating system further includes a third pump interposed between the ejector and the condenser for increasing the pressure of the refrigerant flowing from the ejector.
It is desirable that the refrigerating system further includes a cooler interposed between the first pump and the third pump for decreasing the temperature of the refrigerant flowing from the first pump.
In another aspect of the present invention, there is also provided a refrigerating system including: a compressor for compressing and pumping refrigerant; a condenser connected to the compressor for condensing the refrigerant pumped by the compressor by means of cooling water; and an evaporator having two closed chambers and connected to the condenser for evaporating the refrigerant flowing from the condenser while making the refrigerant flowing through the chambers thereof vertically or horizontally.
It is desirable that the refrigerating system further includes a controller for controlling the overall operation of the refrigerating system.
It is desirable that the refrigerating system further includes a cooling water container for circulating the cooling water therethrough, the condenser being installed inside the cooling water container.
It is desirable that the cooling water container is a split-type, and a part of the refrigerant flowing from a first cooling water container is introduced to a second cooling water container.